Dissertations / Theses on the topic 'Copolymers – Thermal properties'

Natural-synthetic hydrid biomaterials have been isolated from the growth of Alcaligenes latus and Pseudomonas oleovorans in the presence of diethylene glycol (DEG). A. latus could cometabolise DEG with 10 g/L glucose, while DEG was consumed by P. oleovorans with 20 mM sodium octanoate or octanoic acid. The presence of DEG in bioprocessing systems for the production of short chain length (scl-) and medium chain length (mcl-) PHAs consequently lowered cell viability and PHA yield. Cell morphology was slightly changed, but the PHA inclusion bodies apparently were not. DEG affected the composition of the mclPHA which was confirmed to be polyhydroxyoctanoate (PHO) with a significant increase in the C8 component. Gas chromatography-mass spectrometry (GC-MS) was used to quantitatively monitor DEG in the system and revealed its cellular adsorption. Intracellularly, the DEG significantly decreased the molar weight of the mclPHA and sclPHA. P1PH NMR, 2-D COSY and HSQC spectra confirmed that the polymer samples consisted of PHA chains terminated by DEG. Similar to the cultivation of P. oleovorans with DEG, the presence of PEG200 and PEG400 also had an effect on cell growth, PHO yield and cell viability. Furthermore, a hybrid copolymer of PHO-PEG200 was synthesised. The synthesis of these natural-synthetic hybrid copolymers could lead the way for a wide variety of PHA-PEG copolymers with a range of bioactive properties. All thermal properties of PHB were higher than those of PHB-DEG. This may be due to a combination of lower PHB molecular weight and termination of the chains by DEG, i.e. ???DEGylation???. However, PHB-DEG was more elastomeric when compared to PHB, showing properties similar to its copolymer with 20 mol% 3-hydroxyvalerate. Contact angles revealed that the PHB-DEG film was slightly more hydrophilic than PHB. Despite the large difference in their respective proportions, the comparatively small DEG component exerted an influence on chain confirmation, such that solvent casting under humid conditions apparently induced self-assembly and formed a disordered microporous film. DEGylation of PHO also had noticeable effects on the physiochemical properties of the biopolymer. A major decrease in molecular weight, together with the termination of hydrophobic PHO chains with hydrophilic end-groups resulted in changes to its thermal properties when compared to PHO. In comparison to PHO, solvent cast films of PHO-DEG were apparently less flexible, but more hydrophilic.

The structure-property relationships for various segmented copolymers were investigated. A number of mechanical and thermal characteristics were determined. The morphology was characterized by SAXS with respect to size and dispersion of domains; degree of phase separation and the domain interfacial thickness. a. Novel segmented copolymers were synthesized using amino terminated polydimethylsiloxane oligomers as the soft component and various hard component. lt was found that the performance of these copolymers was affected by the varying the hard segment linkages, hard segment content, soft segment MW, stiffness of the siloxane backbone, and amount of chain extender. Two-phase nature of these copolymers was verified by dynamic mechanical, thermal, and SAXS studies. The phase separation was found to occur in these copolymers with as little as 6% HS. These materials displayed behavior similar to the segmented polyurethanes and were found to be superior to the unfilled silicone elastomers. The final materials were used as reasonable models for investigating various methods for determining the interfacial layer thickness between the hard and soft phase. Specifically, due to the fact that there is no hard segment length distribution as is the usual case for segmented urethanes, these materials have some degree of model characteristics. Utilizing Porod's law, and appropriate analysis, both positive and negative deviations were found in the systematic series of copolymers with the degree of positive and negative character dependent upon composition. Negative deviations were accounted for in terms of a finite interfacial thickness which turned out to be relatively small as anticipated, while the positive deviations arose due to isolated hard segments that reside within the soft segment matrix, concentration fluctuations. ln calculating the interfacial thickness, several methods were applied and in general, close agreement was obtained. Finally, correlation function analysis in conjunction with determination of the coherent Porod lengths, etc. were determined and discussed accordingly. b. The structure-property behavior of novel 'water extended' segmented polyurethane-urea copolymers was also investigated. These copolymers were synthesized by utilizing the dehydration characteristics of tertiary alcohols at sufficiently high temperature in weak acidic medium. Mechanical, thermal, dynamic mechanical, and x-ray experiments were carried out to characterize the morphology and properties of these segmented copolymers of systematically varying hard segment content, soft segment MW, block length, and hard segment type. lt was observed that these properties depended primarily on the degree of order in the hard domains and the order could be improved by increasing either the HS content at constant soft segment MW or soft segment molecular weight at the same HS content. The results obtained for these materials were compared with those from conventional polyurethanes to investigate the effect of intermolecular hydrogen bonding on molecular arrangement. c. The final series of segmented copolymers studied were based on polysulfone and polydimethylsiloxane, synthesized by solution polymerization. lt is shown that by varying the length of the segments for each phase and their relative content, it is possible to alter the mechanical and thermal characteristics. The mechanical response was also influenced according to which phase is predominantly continuous. In addition to dynamic mechanical and SAXS measurements, the evidence of the two-phase structure was obtained by TEM.
Ph. D.
incomplete_metadata

Thesis (MSc)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Polystyrene-block-poly(ethylene oxide) (PS-b-PEO) copolymers contain a hydrophilic PEO block and a hydrophobic PS block. PS and PEO have different affinities for most organic solvents and as a result, the PS-b-PEO copolymers are difficult to characterize in solution. In order to achieve a complete characterization of their molecular heterogeneity different techniques have been used. Recently FFF has become a cutting edge technology for polymer analysis because it possesses a number of advantages over conventional SEC and other liquid chromatographic techniques. The mild operating conditions allow the analysis of delicate and sensitive complex analytes such as complex polymer assemblies. The ability to analyze polymers with ultrahigh molar masses has also contributed to its significance in the characterization of polymers. In this study, the FFF behaviour of PS-b-PEO copolymers as well as PS and PEO homopolymers was investigated using Thermal FFF in different organic solvents and AF4. The aim of the study was the correlation of the thermodynamic quality of the solvents and the elution behaviour of the polymers. Unfortunately, PEO homopolymers have been found to interact with the membrane in AF4. Therefore, they were best characterized in organic solvents using Thermal FFF. In contrast to AF4 no specific interactions occurred due to the absence of a membrane. Results for Thermal FFF showed that in all utilized solvents, PS and PEO homopolymers were separated in the direction of increasing molar mass. For PS-b-PEO copolymers the retention in selective (good) solvents for PS was dependent on the molar mass of the PS block in the block copolymer. This was explained by the fact that in poor solvents PEO adopts a collapsed coil conformation while PS is present in extended random coil conformation. Results also showed that polymer retention was dependent on the temperature programme utilized. The fractionations by Thermal FFF indicated that some of the PS-b-PEO copolymer samples contained PS and PEO homopolymers as by-products. After semi-preparative fractionation these homopolymers were qualitatively identified using FTIR spectroscopy.
AFRIKAANSE OPSOMMING: Polistireen-blok-poli(etileenoksied) (PS-b-PEO) ko-polimere bevat 'n hidrofiliese politetileen oksied (PEO) blok en 'n hidrofobiese polistireen (PS) blok. PS en PEO het verskillende affiniteite vir die meeste organiese oplosmiddels, dit bemoeilik die karakterisering van PS-b-PEO ko-polimere in oplossing. Ten einde 'n volledige karakterisering van hul molekulêre heterogeniteit te bepaal moet ‘n verskeidenheid van tegnieke gebruik word. Onlangs het veldvloeifraksionering (FFF) baie grond gewen tov polimeer analise, aangesien dit verskeie voordele het bo tradisionele chromatografiese tegnieke soos grootte-uitsluitingschromatografie (SEC). Die ligte operasionele omstandighede laat die ontleding van ‘n verskeidenheid van polimere toe, enige iets van delikate polimeer komplekse tot ultra hoë molekulêre massa. In hierdie studie is die FFF gedrag van PS-b-PEO ko-polimere asook PS en PEO homopolimere ondersoek met behulp van Termiese FFF(ThFFF) in verskillende organiese oplosmiddels en onsimmetriese vloei-veldvloeifraksionering(AF4). Die doel van die studie was om die verband tussen die termodinamiese gehalte van die oplosmiddels en die eluering gedrag van die polimere te bepaal. Analise van PEO homopolimere was onsuksesvol aangesien daar interaksie was met die membraan. PEO is dus net geanaliseer in organise oplosmiddels met behulp van ThFFF, aangesien daar geen membraan is nie. Analise met ThFFF het gewys dat skeiding plaasvind volgens ‘n toename in molekulêre massa in organise oplosmiddels. Vir PS-b-PEO ko-polimere die retensie in selektiewe (goeie) oplosmiddels vir PS was afhanklik van die molekulêre massa van die PS blok in die ko-polimeer. ‘n Moontlike teorie is dat die PEO blok ‘n ineengestorte spoel struktuur vorm terwyl die PS blok ‘n uitgestrekte lukraake vorm aan neem. Resultate het ook getoon dat die polimeer retensie afhanklik was van die temperatuur program wat gebruik is. Die fraksionering deur ThFFF het aangedui dat sommige van die PS-b-PEO kopolimeer monsters bestaan het uit PS en PEO homopolimere as by-produkte. Hierdie is kwalitatief bewys deur analise van die fraksies na fraksionering van die ko-polimere met behulp van FTIR spektroskopie.

La plupart des couches d'isolation de câbles pour la moyenne tension "MV" et haute tension "HV" sont fabriquées en polyéthylène réticulé (XLPE) par voie peroxyde. L'impact des sous-produits de réaction sur les propriétés et la nécessité d'une étape de dégazage au cours du processus sont les principaux problèmes liés à cette technologie. Cette étude se concentre sur le développement d'une méthode de réticulation alternative sans les problèmes liés aux sous-produits. Des copolymères d’éthylène/époxy ont été réticulés thermiquement en utilisant un agent aminoacide pour créer des liaisons covalentes entre les fonctions époxydes. L’influence de différents paramètres sur la cinétique de réaction tels que la température de réticulation, les proportions aminoacide/époxy, la taille des particules de l’aminoacide et la teneur en époxy dans les copolymères a été étudiée par techniques de caractérisation telles que : rhéologie dynamique, spectrométrie FTIR, microscopie à balayage électronique et calorimétrie différentielle. En outre, l'étude de la structure du réseau avant et pendant un vieillissement thermique a été effectuée par différentes techniques (mesures de gonflement, spectroscopie FTIR, propriétés de traction et thermoporosimétrie) sur deux types de réseaux : un pré-contraint et un autre non-contraint. Enfin, une caractérisation des propriétés électriques par spectroscopie diélectriques et mesures de claquage électrique a été faite. Les résultats concernant les cinétiques de réaction, les propriétés thermomécaniques et le comportement électrique ont montré que la formulation développée dans cette étude peut être utilisée pour une application de câble
Most of insulation layers of cables for medium voltage “MV” and high voltage “HV” applications are made of crosslinked polyethylene (XLPE) by peroxide technology. The impact of reaction by-products on properties and the consequential need of a degassing stage during the process are the main problems related to this technology. This study focuses on the development of an alternative crosslinking method without by-products issues. Epoxy-ethylene copolymers were thermally crosslinked by using an amino-acid agent to create covalent cross-links between epoxide functions. Influence of several parameters on kinetic reactions such as crosslinking temperature, amino acid/epoxy proportions, size particle of amino acid and epoxy content in copolymers were studied by characterization techniques such as: dynamic rheology, FTIR spectrometry, SEM microscopy and differential calorimetry. In addition, study of the network structure before and during a thermal aging was done on a pre-constrained and a non-constrained network by different techniques (swelling ratio measurement, FTIR spectroscopy, tensile properties and thermoporosimetry analysis). Finally, a characterization of electrical properties by dielectric spectroscopy and breakdown measurements was done. Results related to reaction kinetic, thermo-mechanical properties and electrical behavior have shown that the developed formulation can be used for cable application

Made available in DSpace on 2014-10-09T12:51:42Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:08:37Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

"May 2003"
Includes bibliographical references (leaves 261-270)
xvi, 271, [16] leaves : ill. ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, School of Chemistry and Physics, 2003

碩士
國立宜蘭大學
化學工程與材料工程學系碩士班
98
The tri-block copolymers of poly (L-lactic acid) (PLLA) and polycarbonate were prepared by ring opening polymerization of L-lactide by poly- carbonatediols of different molecular weights. The crystalline behavior and properties of the tri-block copolymers were daracterized by differential scanning calorimetry(DSC), polarized optical microscopy(POM), wide angle X-ray diff- raction(WAXD) and thermogravimetric analyzer(TGA). The thermal properties and crystalline properties of the tri-block co- polymers were found to be influenced by the PLA content and the molecular weight of the polycarbonatediols used. The PLA segments could crystallize after annealing. As the PLA content increased, or as the molecular weight of the PCDL increased, the melting point and the crystallinity of the PLA segments followed an increasing trend. The tri-block copolymers were found to exhibit only a glass transition temperature (Tg), and the Tg increased as the PLA content increased. This indicates that the PLA segments would be miscible with polycarbonate segments, since the two segments would be miscible, the PLA segments of some tri-block copolymers were difficult to crystallize, and their second run DSC heating curves exhibited an exothermic peak due to cold crystallization. The trend of the X-ray diffraction patterms was roughly consistent with the DSC data. Pure PLA could develop typical spherulite structure, the developing phenomenon of the spherulite of some tri-block copolymers of longer PLA block length was more or less similar to that of pure PLA. A major difference is that there were obvious disruptions in the spherulites for the tri-block copolymers. As the PCDL content increased the trend of disruption increased, as expect. Some tri-block copolymers of shorter PLA block length exhibited no significant spherulite structure and crystalline phase tends to be discrete. The trend could be described as the results of dilution effect and the effect of good miscibility between the two segments.

博士
國立臺灣科技大學
高分子系
96
Two series of Polyurethane copolymers, Poly(siloxane/tetramethyl ether-urethane) copolymer (MB) and Poly(siloxane/tetramethyl ether-imide) urethane copolymer (MD), were synthesized in this study. The chain extenders of copolymers are differential, 1,4-butane diol (1,4-BD) and 3,3’,4,4’-diphenylsulfonetetracarboxylic dianhydride (DSDA). The soft segments of both copolymers consist of polytetramethylene glycol (PTMG) and polydimethylsiloxane diol (PDMS). The hard segments of MB copolymer include urethane B which is consisted of 4,4-diphenylmethane diisocyanate (MDI) and 1,4-BD, urethane G consisted of MDI and PTMG, and urethane S consisted of MDI and PDMS. For the MD copolymer, the hard segments are urethane G, urethane S and imide segment due to the DSDA instead of 1,4-BD. The various urethane hard segments of copolymers lead to various thermal degradation behaviors by TGA. The TG/DTG curves of MB copolymer show the degradation regions of urethane B, urethane G and urethane S are 200~300 °C, 310~370 °C and 280~350 °C, respectively. The degradation regions of urethane G and urethane S are unable to distinguish for samples with PTMG and PDMS mixed soft segments due to the overlapping degradation regions of urethane G and urethane S. The TG/DTG curves of MD copolymer in the degradation regions of hard segments only show the degradation of urethane G and urethane S due to the degradation temperature of imide segments above 350 °C. The degradation behaviors of soft segments are affected by the contents of PDMS and PTMG. The DTG curves of MB copolymer in the degradation regions of soft segments display the degradated peak from a single peak, a single peak with shoulder to double peak as the PTMG content increases. The degradation regions of soft segments for MD copolymer include the degradation behaviors of PDMS, PTMG and imide segment. The degradation regions of these segments show overlap, resulting in a wide degradated peak in the DTG curves. The samples with high PDMS contents present a minor shoulder above 520 °C. PDMS degrades into high molecular weight macrocyclics through interchange reaction and the macrocyclics initially degrade above 520 °C. TG-IR is used to analyze the degraded gas products of copolymers in various temperatures. Combining TGA and TG-IR analysis, the degradation mechanisms of copolymers can be further set up. Four degradation kinetic methods, Friedman, Kissinger, Ozawa and Horowitz-Metzger methods, are proposed to investigate the thermal degradation kinetics of copolymers. Various kinetic methods result in various activation energies. But, they demonstrate that hard segments of urethane B, urethane G and urethane S present individually degradation step. Therefore, incorporating PDMS or imide segment into copolymers can significantly enhance the activation energies and improve the thermal stability. The phase-separation degree of copolymers with PTMG and PDMS mixed soft segments is lower than that the polyurethane with PDMS soft segment because the copolymers incorporate PTMG in the soft-segment to increase the miscibility between soft segment and hard segment. The MB and MD copolymers in the differential scanning calorimeter (DSC) exhibit soft- and hard-segmented phase-transition. The soft-segmented phase-transition MB and MD including the PDMS and PTMG amorphous phase-transition but the crystal phase-transition only presents on the melting-quenched MD copolymers. The thermal behavior of amorphous hard segment for the copolymer with PDMS soft segment and 62.3 % hard-segment content is studied by differential scanning calorimetry (DSC). Upon annealing at 100 °C, both the T1 temperature and magnitude of the T1 endotherm increase linearly with the increase in logarithmic annealing time. This phenomenon is typical of enthalpy relaxation resulting from the physical aging of amorphous hard segment. Upon annealing above 100 °C, the T1 endotherm shifts to high temperature until its mergers with the T2 endothermic temperature. Following annealing at 170 °C for various periods, the DSC curves present two endothermic regions. The first endotherm assigned as T2 is the result of the enthalpy relaxation of the hard segment. The second endothermic peak (T3) is caused by the hard-segment crystal. The exothermic curves at an annealing temperature of above 150 °C exhibit an exotherm caused by the T3 microcrystalline growth. The DSC curves of sample with PTMG and PDMS mixed soft segments show there are two endothermal regions, which are respectively the short-range ordering and the long-range ordering of hard segment domains (Region I and II). The endothermic behavior demonstrated by annealing is an enthalpy relaxation resulting from prolonged physical aging. Furthermore, the hard-segmented crystal (Region III) appears on the high hard-segment content of sample annealing for a period. The dynamic mechanical analyses show that the decreasing E΄ of MB copolymer becomes slow as the PTMG content increase. The tanδ indicate that the width of α peak become board as the ratios of PTMG and PDMS vary. The E΄ curves of MD copolymer show the incorporating of DSDA causes the high E΄ at high temperature. The s-s curves of MB copolymer present strain-induced crystalline with the blending of PTMG, so the sample have excellent mechanical properties. The MD copolymer displays low elongation due to imide group. Therefore, sample is incaple of high strength.

碩士
國立臺北科技大學
化學工程研究所
95
The main objective of this study was to investigate the effect of organoclay addition on thermal and fire properties of low density polyethylene (LDPE) foam and Ethylene Vinyl Acetate copolymer (EVA). Nanoclay、P-N type intumescent flame retardant、cross-linking agent and blow agent have been mixed with LDPE to prepare flame-retarded LDPE foam. LOI and cone calorimeter (CONE) experiments showed that the presence of organoclay in the flame-retarded LDPE foam was not only improve its thermal stability but also reduce its maximum heat release rate and extinction coefficient. EVA/CLAY hybrids have been prepared by melt-blending. The exfoliated structures of clay in the hybrid were characterized by XRD and TEM. TGA and cone calorimeter data shown that nanoclay improve the degradation pathway and also improve its thermal stability.

碩士
國立臺北科技大學
分子科學與工程系有機高分子碩士班
106
Currently, PA6 (Polyamide 6) is an inexpensive and important commercial thermoplastic. Moreover, aliphatic polyamides contain good mechanical property. Therefore, the theme of this study is based on the PA6 copolymers. The diamines of copolymerized materials in this study are caprolactam (ε-CPL), ethylenediamine (EDA) and hexamethylenediamine (HMDA), they are the widely available and low-cost materials. In this study, in order to synthesize the nylon copolymers, the synthesis was divided into three processes: Firstly, synthesize the nylon monomer BAEA. Secondly, one of nylon salts is synthesized from BAEA diamine monomer, and the diamine of nylon materials is respectively replaced by two kinds of nylon salts, including ethylenediamine derivatives (EDAs) and diamine derivatives (HMDAs); on the other hand, the diacid of nylon materials is replaced by 1,4-cyclohexanedicarboxylic acid (CHDA). Finally, the two kinds of nylon salts are copolymerized with PA6. All things respected that this study have developed one kind of nylon material with a low melting point, a high glass transfer temperature, and a more environmentally friendly and higher performance. In the end, the experimental detection of this paper uses Nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectrometer (FTIR) for the identification of the material structure of polyamides; Besides, Differential scanning calorimeter (DSC), Dynamic mechanical analysis (DMA) and Thermogravimetric analyzer (TGA) were used to analyze the thermal properties, and, last but not least , the mechanical properties have been characterized by Impact test and Tensile test. Ultimately, the twin-screw melt spinning was investigated to determine the hygroscopicity properties.

碩士
國立臺北科技大學
化學工程研究所
99
This study aims to prepare nanocomposites of ethylene vinyl acetate copolymer with lamellar materials(ex: organically modified montmorillonites, mica, Mg-Al-layered double hydroxides) and graphite materials (ex: expandable graphite and exfoliated graphite nanoplatelets) respectively with the technique of melt blending. The product thermal, combustion and mechanical properties were tested by thermogravimetric analysis, cone calorimeter and tensilon in sequence. Results from TGA analysis showed that the thermal degradation temperature were increased 48.6℃by adding organically modified montmorillonites with 5wt%. Otherwise, adding exfoliated graphite nanoplatelets with 5wt% increased the thermal degradation temperature 16.5℃. In cone calorimeter test, it showed that the peak heat release rate (pHRR) and extinction coefficient were reduced significantly. The pHRR of EVA/5wt% graphite materials were decreased about 50% in compared with pure EVA. Finally, in the mechanical test adding lamellar materials and graphite materials always have positive effects in Young’s modulus.

碩士
國立臺北科技大學
化學工程研究所
101
This study focused on the flame retardancy of ethylene-vinyl acetate copolymer (EVA) in combination with metal hydroxide and exfoliated graphite nano-platelets (xGnP). Also, this study implemented four types of fire test analysis, such as LOI, UL-94, and cone calorimeter for the metal hydroxide and the exfoliated graphite nano-platelets in EVA composites. The experimental results showed that when the xGnP was substituted for the aluminum hydroxide or magnesium hydroxide in EVA blends. When the xGnP added into the polymer, LOI value was improved, the UL-94 reached the V-0 rank, besides, the thermal gravimetric analysis (TGA) also showed that the xGnP increased the thermal stability and cone calorimeter test indicated that the peak heat released rate (pk-HRR) is reduced by 56%-70%.

碩士
輔仁大學
化學系
106
The research is mainly divided into two parts. The first part is about the synthesis and properties of low-band gap polymer in the active layer of organic solar cells. The second part is about the effect of high-efficiency and low-band gap polymer on the planar heterogeneous interface under different heat treatment conditions. High efficiency organic polymer solar cells are based on low-band gap polymers which use push-pull concept to adjust the energy level to match the sunlight spectrum. Many high-efficiency low-band gap polymers in the literature use the benzo [1,2-b: 4,5-b '] dithiophene (BDT) derivatives as push structures but the synthesized polymers are not crystalline. If BDT derivatives with crystallinity can be synthesized, carrier mobility and the efficiency can be increased. In this study, a symmetric monomer based on BDT was synthesized. Its structure was characterized by 1H-NMR and IR. A low-band gap polymer PDABDT with this symmetric structure monomer was synthesized. Due to the symmetry of its molecular structure, the synthesized polymer, characterized by powder diffraction XRD shows characteristic peak at 2θ = 4.93˚, indicating that PDABDT is a crystalline polymer. At the same time, absorption spectroscopy (UV-Vis) measurement showsλmax = 550 nm and its energy gap size is 1.75 eV at λonset = 700 nm. In the second part, this study designs a new method of fabrication that utilize planar heterojunction concept following by thermal process to control the interfacial area of the material to make bulk heterojunction with buffer layer under different heating conditions. Melting point of PffBT4T-2OD was measured by DSC. After heating above the melting point, it was cooling under different cooling conditions to study its crystallization behavior. When the cooling rate was increased and the arrangement became better, the absorption spectrum was red shifted phenomenon, and the crystallization peak signal has the tendency of enhancement. The PffBT4T-2OD films with different cooling conditions were characterized by Fluorescence Spectroscopy, X-ray Diffraction, and Absorption Spectroscopy. Experimental results indicate an enhanced crystallization at a fast cooling rate.